You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
35 lines
1.1 KiB
Racket
35 lines
1.1 KiB
Racket
#lang racket/base
|
|
(require racket/class "helper.rkt" "util.rkt")
|
|
(provide (all-defined-out))
|
|
|
|
#|
|
|
approximates
|
|
https://github.com/mbutterick/restructure/blob/master/src/Reserved.coffee
|
|
|#
|
|
|
|
(define x:reserved%
|
|
(class xenobase%
|
|
(super-new)
|
|
(init-field [(@type type)] [(@count count)])
|
|
|
|
(unless (xenomorphic-type? @type)
|
|
(raise-argument-error '+xoptional "xenomorphic type" @type))
|
|
|
|
(define/augment (x:decode port parent)
|
|
(pos port (+ (pos port) (x:size #f parent)))
|
|
(void))
|
|
|
|
(define/augment (x:encode val port [parent #f])
|
|
(make-bytes (x:size val parent) 0))
|
|
|
|
(define/augment (x:size [val #f] [parent #f])
|
|
(* (send @type x:size) (resolve-length @count #f parent)))))
|
|
|
|
(define (x:reserved [type-arg #f] [count-arg #f]
|
|
#:type [type-kwarg #f]
|
|
#:count [count-kwarg #f]
|
|
#:pre-encode [pre-proc #f]
|
|
#:post-decode [post-proc #f])
|
|
(define type (or type-arg type-kwarg))
|
|
(define count (or count-arg count-kwarg 1))
|
|
(new (generate-subclass x:reserved% pre-proc post-proc) [type type] [count count])) |